Reciprocating piston meter



I Dec. 21, 1943. H. CHRJSMAN ETAL RECIPROCATING PISTON METER 5Sheets-Sheet 1 Filed Dec. 12, l940 Dec. 21, 1943. H. CHRlSMAN T AL2,337,310

REGIPROGATING PISTON METER 3 Sheets-Sheei 2 Filed Dec. 12, 1940INVENTORS //0ram Chas/ 7700.

Q0/2765 Fe/a M?- I ATTOR E H. CHRISMAN ET AL 2,337,310

RECIPROCATTNG PISTON METER M07955 P's/g ATTQ Y Patented Dec. 21, 1943UNITED STATES PATENT OFFICE 2,337,310 RECI PROCAT ING P'is'roN HoraceChrisman, Edgewood, and James F. Reid; Rosedale, Pa., assignors toPittsburgh Equit able Meter Company, Pittsburgh; Pa-., a corpo-' rationof Pennsylvania Application December 12, 1946, Serial No. 369,776

3 Claims.

This invention relates to positive displacement meters for measuringvarious kinds of fluids.

It is an object of this invention to produce a meter of the positivedisplacement type which will operate on a relatively small pressurehead.

A further object is the provision of a meter which is compact and simpleto make and assemble.

A further object is the provision of a piston meter in which the pistonsand crank shaft can be assembled into a unit and the unit inserted inplace or removed for disassembly.

A further object is the provision of a piston meter which is freerunning and has a smooth non-pulsating action.

These and other objects will be apparent upon consideration of thefollowing specification taken in connection with the accompanyingdrawings showing preferred embodiments of the invention, and wherein,

Figure 1 is a view in embodiment,

Figure 2 is a plan View of Figure 1 with the valve and valve casingremoved,

Figure 3 is a vertical sectional view of the easing and valve seat ofFigure 1 taken on line IIIIII of Figure 2,

Figure 4 is a plan View of the valve,

Figure 5 is a side View of the valve,

Figure 6 is an end view of the crank assembly,

Figure 7 is a bottom view of the valve seat,

Figure 8 is a vertical sectional view of the preferred modification,Figure 9 is a horizfontal sectional View of Figure 8 taken on linelX-TX, and Figure 10 is a vertical sectional view of the piston andcrank assembly,

Figures 11 to 17 are diagrammatic views illustrating the operation ofthe meter, and Figure 18 is an enlarged view of a detail of Figure 10.

Referring to the drawings (Figure 1), there is shown a casing I whichpreferably comprises a casting of suitable dimensions having a bore 2therein running from end to end thereof closed at its ends by covers 3and 4 which are secured in place by cap screws 5 threaded into thecasing or in any other suitable manner. The bore 2 contains two pistons6 and l and thus forms three chambers 8, 9 and l in which the pistonsoperate. One side of the casing is bored and tapped at l3 to receive ahexagonal bushing l4 therein which the valve driving shaft I5 isjournalled. The other face of the casing is drilled and tapped at It toreceive a recessed screw ll having a ball I!) located therein. Crankmember l9 has its stub shafts 20 and 2| journalled in the ends ofbushings I 4 and screw ll and is coupled to the shaft l5 by means of asquare tongue and square recess connection or in any other suitablemanner. A cap 22 threaded in a recess 23 in the casing protects thescrew ll.

vertical section of an I9 preferably is constru te as shown in Flglll'eS1 and 6 with ainiddle connecting arm 24 having spaced pins 25 and 26passi g therethrough and held in place by a cross pin 21. The end ofcrank pin 25 e ters one enact cran arm 28 which has the stub or shaft 20secured thereto, a pin 29 holding the arm 28, pin 25 and shaft 29assembled. Similarly pin 26 enters oh' end of crank arni 3| having thestub shaft 2l therein and which is new by a pin 33. Tnusg, the crankpins 25 and 26 are disposed at co no'm each other and from the stubshafts 2|] and 2|. The pistons 6 and 7 have offset connecting rods 35and 36, each secured at one end to' its respec tive piston head by a pin31 assing through the boss 38 and having a pressed fit therein. Caps 40threaded on the ends of bosses 38 form a sealing fit with: the heads ofthe pistons and enclose the'ends of the connecting rods. At their otherends the connecting rods have bores which receive the crank pins 25 and26, the connecting rods being assembled thereon before the crankassembly is" pinned together. As the stub shafts 20 and 2! do noteiitendbeyond the diainetero'f the bore 2, it will be apparent that the w olepiston and crank assembly may be assembled outside of the casing andinserted or removed as a unit, by first removing the bu hings M' and fl.

The casing has a bore 43 in its upper surface surrounding bushing Mwhich connects with passages 44 and 45 serving to supply and exhaustfluid to and from the ends of cylinders 8 and I0, and a vertical bore 46(Figure 3) connects with the central chamber 9. The upper surface of thecasing is machined to receive a flanged valve seat member 48 having a'central boss 49 (Figure 7) which forms a sealing fitl with the bore 43,and seat 48 has openings 5t, 52 and 53 therein, separated by webs 54, 55and 5'6. A central opening 51 surrounding bushing M is provided in thevalve seat which connects witha recess 58 serving as an exhaust port.Boss 49 has recesses 59 therein and when the valve seat is assembled tothe body, the opening 5! connects with supply here through a recess 59,opening 53 connects with supply passage 44 through another recess 59 andopening 52 connects with supply passage 45 through a third recess 59while recess 58 connects with a lateral bore 60 in the casing (Figures 2and 3) serving as" the exhaust connection.

A Valve membef fil is secured to the shaft l5 bymea'ns of a set screw 62which allows adjustmerit of the timing thereof. In assembly the valve isfirst secured to the shaft [5 by the'set screw 62 and when the tintingis accurately a'djll std a 1io Ie53- (Figures 4 and 5) is drilledtherethrough to receive the pin 64 by which the valve is rigidly securedto the shaft I 5. The valve is surrounded by a cover 65 having an inletCrank ember bushing I4, thus allowing a running the order of a few ing,port port 66 therethrough, and a register driving shaft 61 passesthrough the stuffing box 58 of the cover and is coupled to the shaft I5by a pin'and slot connection or in any other suitable manner.

Preferably, the valve 6| 69 which rests on a clearance on tween the topsurface of under surface 1| of the'valve. face of the valve has anopening 12 which is 90 in arcuate extent and is diametrically oppositerecess 13 which also is 90 in arcuate' extent. Thus two lands, 14 and 15are provided which are 90 in arcuate extent, which co-operate with theports 5|, 52 and 53, each of which is 90 in arouate extent separated bywebs 54, 55 and 56, each of which are 30 in arcuate extent. Theoperation now will be described with particular reference to'thediagrammatic views in Figures 11 to 1'1, in which the partsdiagrammatically shown are numbered according to Figures 1 to '1. Whenthe pistons 6 and 1 are in the positionshown in Figure 1, the crankassumes the position shown in Figure 6 and diagrammatically representedin Figure 11. In this position 30 of ports 52 and 53 are uncovered bythe intake recess 13 so that, fluid is being supplied to chambers 8 andfull communication with port 5|. Pistons 6 and '1 are moving toward thecenter to reduce the size of chamber 9 and causing this chamber toexhaust. When the crank has moved 30 to the position shown in Figure 12,piston 6 is at the inner limit of vits stroke and port 53 is closed offcompletely by land 15. Piston 1 is still moving toward the center andport 52 is still connected by 60 to the intake recess 13. Port 5| isstill exhausting as piston 1 is approaching piston6. Upon another 30movement of the crank the pistons, have assumed the position shown inFigure 13', in which they are still approaching each other althoughmoving in the same direction, and thus chamber 9 is still decreasing.Port 5| still is exposed 30 and is exhausting and port 53 now is exposed30 and also "is exhausting as the piston moves outward. Port 52 iscompletely uncovered and chamber I is still intaking. Upon another 30movement the crank assumes the position shown in Figure 14 in whichcrank pins 25 and '26 are equidistant from the vertical center line.Pistons 6 and 1 now are moving toward the leftat aboutthe same speed sothat the volume of chamber 9 is constant and port now is completelyclosed. Port 53 is still exposed 60 and is exhausting and port 52 isuncovered 60 by intake recess 13 and is intaking.

Upon a further movement of 30 the crank assumes the position shown inFigure 15 in which in the same direction but the pistons are movingfaster than piston 1 and piston 6 now is moving has an under surface Iwasher located on top of I0, while exhaust opening 12 is in continues toexhaust and port 5| intakes.

thousandths of an inch be V valve plate 48 and the;

'- The under sura clear without-tracing :the cycle of operation.

its movement, as shown in Figure 17, and port 52 becomes exposed 30 tothe exhaust outlet 12, while chamber 9 continues to intake and chamber 8continues to exhaust. Upon a further 30 turn, piston 6 reaches deadcenter position, and

port 53 becomes completely closed, while port 52 It is believed theoperation of the meter will thus be through the other half of f In themodification shown in Figures 8, 9 and V 10, wherein like parts aredesignated by like refthus the chamber 9 is increasing in size. Thus, I

erence numerals, the pistons I40 and MI have semi-cylindrical skirtportions I42 and I43 respectively with slots I44 and I45 therein intowhich extend the ends of shafts 20 and 2|. skirt portions preventcanting and guide the pistons in their movement. Each piston skirt hastwo rods I46 and I41 extending through the skirt to provide a slotbetween the rods in which the crank pins 25 and 26 are received, thepins being held in position by a spring wire I49 in each piston passingbetween rods I46 and I41 in circumferential grooves provided in the rodsand bent upward under rod I41 and coiled about a screw I5I, the free endof the spring being bent downward and abutting the piston head.

In operation the semi-cylindrical skirts I42 and I43 interfit so thatwhen the pistons are in the position corresponding to Figure 14 theyform a substantially continuous hollow piston, both pistons movingtogether for a small portion of the cycle of movement. This enables themeter to be made more compact, as there is no connecting rod needed toconnect the pistons to the crank.

What we claim as our invention and desire to secure by United StatesLetters Patent is:

1. A piston meter comprising a casing having a bore therein, two-pistonsin said bore, end closures for said bore whereby three chambers areprovided, a crank assembly comprising two stub shafts having crank pinstherebetween, said crank assembly from the end of one stub shaft to theend of the other stub shaft being of a length less than the diameter ofthe bore, means connecting said pistons and crank pins and removablebearing members in said casing extending into said bore for journallingsaid stub shafts. I

2. A piston meter comprising a casing having a bore therein, two pistonsin said bore, end closures for said bore whereby three chambers areprovided, a crank having crank pins disposed at an angle of sixtydegrees,said pistons having transverse slots co-operating with the crankpins, and interfitting skirt portions, and a valve operatedby said crankfor controlling admission and exhaust of fluid'from said chambers. w

3. A piston meter comprising a casing having a bore therein, two pistonsin said bore, end 010- sures for said bore whereby three chambers areprovided, a crankshaft having crank pins disposed therein, said pistonshaving transverse slots co-operating with the crank pins andinterfitting skirt portions, and a valve operated by said crankshaft forcontrolling admission and exhaust of fluid from said chambers,

HORACE CHRISMAN; JAMES F. REID.

